Japan, the country where a robot can earn a salary higher than many workers and where more and more people are keeping robots as pets, is playing host for the second time to the world's only exhibition devoted to entertainment robots.

Robodex 2002 begins today in the port city of Yokohama, near Tokyo, and some of the latest advances in robot technology were on display yesterday evening at a preview event.

This year's Robodex not only focuses on robots for entertainment, the main topic of the last Robodex in late 2000, but robots that can coexist and work in a human society. These include robots that educate children, assist people who need medical support and can guard a building at night.

One robot, Honda Motor's Asimo, is already working alongside people in several situations. It landed a job at Japan's National Museum of Emerging Science and Innovation, works as a guide at IBM Japan's building, rang the opening bell at the New York Stock Exchange on Valentine's Day and also stars in a series of Honda TV commercials.

Asimo is one of the two hottest robots at Robodex 2002. The other is Sony's SDR-4X (pictured). Like Asimo, the SDR-4X is a humanoid robot that can walk, move and even dance.

Sony unveiled a prototype of the 58cm-tall robot a week ago. Equipped with an advanced motion-control system, the robot can balance on a moving platform and walk on carpet or Japanese tatami mat floors — something that sounds simple but is very difficult for a robot.

At the preview demonstrations the robots did their best to impress visitors. Four SDR-4X robots sang and danced on a Sony stage along with the company's Aibo entertainment robots, while Honda's Asimo walked around the hall, waved at visitors and climbed up and down stairs.

A total of 27 domestic participants — 13 corporations, 10 universities, three governmental agencies and one individual — and a single foreign country, the UK, represented by firm Shadow Robot, will exhibit their robots at the exhibition, which runs until Sunday.

More information on Robodex can be found online at its website.